Not to steal the thread but i have a similar issue but when its cold, is this normal?

Ha! Yeah mine barely moves until I get going and the fluid starts to warm.
I got a trick that seems to help me with that issue. While I sit and let the engine warm up I hold the clutch and just shift the shifter through the gears. Seems to churned it up enough so I can shift a tad bit easier.

-15 it barely wanted to move.

I also read if you put your t case in neutral and leave your trans in first it will spin the gears and warm it up. I have not tried this yet.

I'm concerned about draining my stinky gear lube out of my trans and running oil or synchromesh. I fear that it won't like the new fluid. Maybe I'm just paranoid?